"This is the largest attack that we've seen," Petro said. He stressed that it didn't affect the company's core domain name system (DNS) services, but administrators had to work fast to get the attack blocked by the backbone Internet companies from which UltraDNS gets its connectivity. "From a network management perspective, it certainly kept us on our toes," he said.
The attack came almost exactly a month after a similar attack targeted the DNS root servers, the databases that hold the critical information computers need to maintain top-level domains. Such domains act as the white pages of the Internet, matching domain names--such as www.cnet.com--with numerical Internet addresses.